Variable-speed hydraulic transmission



Jan. 2 2, 1946. R. s. sEGswoRTH VARIABLE SPEED HYDRAULIC-TRANSMISSIONFiled sep't. 2s, 1944 4 sheets-Sheet 1 InVnor.

, Jan. 22, 1946.

A R. S. SEGSWORTH E VARIABLE SPEED HYDRAULIC TRANSMISSION Filed sept.23, `1944 4 sheets-sheet 2 Inl/anion A 5F15 3 ff |L| Il Il [Il 4 y AJan. Z2, 1946. R. s. sEGswoRTH VARIABLE SPEED HYDRAULIC TRANSMISSION 4shets-sheet 3 Filed Sept. 23, 41944 Jan, u22, 1946.

R. s. sx-:GswoR'rH 4 VARIABLE SPEED HYDRAULIC TRANSMISSION FiledSept.25, 1944 4 Sheets-Sheet 4 l Patented Jan. 22, 1946k f yUru'ml) srA'rVARIABLE-SPEED i" t TRANSMISSION i Y Roberta-'semana Toronto,ontariacanaaa-,

assigner to The GeneraI Engineering. Company i (Canada) Limited,Torontmntario, Canada Applicaties september 2s, 194;',seriaiNi55ssa5This invention relates to hydraulic transmissions in which the drivenAmember may be operated through a. fluid medium at speeds variable inrelation to the speed of the driving member'. and the principal objectis to provide a transmission in4 which the load is constantly connectedwith the driving power and the speed of operationof the driven membermay be varied from zero to maximum by the simple adjustment of a singlemember.

simple and vrugged structure in which the operating iluid will flowfree1y,- thereby reducing fric-v tional losses to the minimum and whichwill require the minimum of attention and 'will be re' markably easy tocontrol. y

The invention consists essentially of a pair of vane type rotors mountedon parallel butlongitudinally onset axes, a cylinder enclosing both ofsaid rotors and engaging the vanes thereof and mounted for adjustment ina direction transverse to the axes of said rotors whereby the volumetricdisplacement per revolution of one rotor is utilized to drive the otherrotor in a direct ratio to the relative adjustment of the enclosingcylinder. l

In the accompanying drawings Figure 1 is a longitudial verticalmid-sectional view of a mechanism constructed in accordance with thisinvention.

Figure 2 is a vertical transverse section of the mechanism taken on theline 2-2 of Figure 1.

Figure 3 is a horizontal plan section taken on the line 3-3 of Figure 1y V Figure 4 is a vertical elevational section taken on the line 4-4 ofFigure 1 through the cylinder and showing the driving rotor. t

Figure 5 is a diagrammatic vertical section of the driving rotor takenon the line 5-5 of Figure 1 showing the cylinder enclosing the rotoraoljusted to the mid-position concentric to the rotor.'

Figure 6 is a diagrammatic vertical elevational section through the linei--S of Figure 1 showing the driven rotor and illustrating the relativeposition of the cylinder to the rotor when said cylinder is in theposition illustrated in Figure 5 relative to the driving rotor.

Figure 'l is a view similar to Figure 5 illustrating the cylinderadjusted to a' position eccentric to the driving rotor. i

Figure 8 is a view similar toFigure 6 showing the position of thecylinder relative to the driven l0Y A further object is to devise anextremely comme Y(c1. so-iissizff t t .accompanying drawings the outercasing-'of the device is formed of a pairjof horizontally dividedsections I and 2 having matingfianges which are suitably boltedtogether.

Journal bushings 3 and 4 are mounted in bosses 5 and 6 at the oppositeends of thecasing and each, bushing is formed with an eccentricallyarrangedbea-ring. orice 3 and 4' respectively, the axes of which areoiset horizontally and are parallel the4 one to the other. The amount ofoffset will be regulated in accordance with the duty for whichthe'machine is designed as will hereinafter appear and may be regulatedbyV rotating,y .the

bushings in their bosses.

Mounted in suitable bearings in the .bushing 3 is the drive shaft Iwhich is connected with any sui-table source of driving' power, andmounted on the innerend of said driving shaft is a cylindrical rotor 8which is provided with a plurality of radial l Awhich are slidablymounted the vanes I0. v

The driven shaft I I journalled insuitablebearings in the bushing 4, theaxis of which is horizontally offset from the axis of the driving shaft1, hasmounted on its inner end the cylindrical rotor I2 which isprovided` with radial slots I3 similar to the s1ots'9 in the rotor 8,and in which radial vanes I4 are slidably arranged.

A cylindercasing I5; arranged within the outer casing formed by thelower and upper sections I and 2, is formed with a pair of co-axialcylindrical chambers I6 and I I arranged at opposite ends, the chamberI6 forming a housing for the rotor 8 and its radial vanes, and thelchamber Il forming a housing for the driven rotor I2 and its radialvanes.

t parallel cylindrical` oriiices'ls and I9 extending` The cylindercasing I5 is formed. with a pair of transversely thereof substantiallymidway of its length and through these orificesv extend respectively thecylindrical bars 2li and 2|, the ends of which are rotatably mounted inbearing. bosses 22 rotor when the cylinder is in the position relativeand 23 arranged respectively in the upper and lower casing sections 2and I. 45

End plates 24 and 25 enclose the outer ends of the cylinder chambers I6and Il respectively of the cylinder casing I5.

A duct 26 is formed in the upper portion of the cylinder I5 and extendslongitudinally thereof between the ports 2l and 23 entering respectivelythecylinder chambers I6 and Il A duct 29 similar to the duct 26 isarranged in the lower half of the casing I5 diametrically opposite tothe duct 26 and forms a communieating 'passage between the ports 30 and3i respectively of the cylinder chambers I6 and Il.

tudinal duct 26 extending from the cylinder' chamber I8 to the chamberI1 and it extends diagonally and opens into the bottom duct 28 extendingfrom the cylinder chamber I6 to the chamber I1. The bottom end of theduct 35 isl however closed by the valve portion 33 of the The duct 34opens at the bottom end into the duct 28 and extends diagonally upwardto communicate with the duct 26 but the duct 34 is closed by the valveportion 32 of the bar 20.

The operation of the rotor 8 with its radial vanes within the cylinderchamber I6 is designed to create a ilow of a fluid medium such as oiltaking it in through the port from the duct 28 and discharging throughthe port 21 into the duct 26, and this uid medium iiows through the duct26 and through .the port 28 and effects the rotative operation of therotor I2 andv its radial Vanes, thereby operating the driven shaft II.

The cylinder casing I5 andjalso the outer casing is completely filledwith the fluid medium, consequently the .ducts 35 and 34 extendingtransversely through the central portion of the cylinder member arelled. Oil forced into the ducts 26 by the operation of the rotor 8 flowsthrough this duct freely `to operate the rotor I2 and the oil enteringthe port 28 and the cylinder chamber I1 is discharged through the port3| into the bottom duct 29 and the discharged oil flows backto thedriving rotor to the port 30.

The cylinder casing |5 has been described as being slidably mounted uponthe bars 20 and 2| and as these bars are arranged transversely of theouter casing the cylinder casing may be mved so that the `positions ofthe rotors mounted on the shafts 1 and I I respectively will be alteredeccentrically of the respective cylinder chambers I6 and I1. v

An operating screw 36 threaded in the boss 31 in one of the side wallsof the outer casing is rotatably secured at its inner end to thecylinder casing I5 so that upon the rotation of said screw member thecylinder casing will Ibe caused tov slide on the bars 28 and 2|.

When the cylinder casing I5 is adjusted so that the cylinder chamber I6is inthe position illustrated in Figure 5 it will be seen that the rotor8 is concentric to the cylinder and that the chambers A enclosed by theradial vanes of the rotor the cylinder chamber I6 changesthe'relationship of the rotor I2 with its enclosing casing I1, but theflow of pressure fluid into' the chambers B between the vanes of thedriven rotor causes said rotor to be operated at a speed which is indirect ratio to the speed of the driving rotor.

It will be understood that as the cylinder I5 is moved further in thedirection of the arrow in Figure 5 the displacement of the motive fluidper revolution from the chambers A of the rotor 8 is progressivelyincreased, while the displacement capacity per revolution of thechambers B of the rotor `I2 are correspondingly decreased, with theresult that there will be an increase in flow of uid from the drivingmember to the driven member, resulting in an increase in the travel ofthe driven member in relation to the driving member. A

The ratio of increase of output speed will vary in accordance with. themovement of the cylinder.

When the cylinder casing I5 and the respective rotors are in thevposition shown in Figures '1 and 8 85 the discharge per revolution fromthe driving rotor will be equal to the receiving capacity per revolutionof the driven rotor, and the output speed will equal the input speed.

Further movement of the cylinder will cre- -I0 ate an increased volumeper revolution from the l position of the cylinder continues to bechanged.

are of equal volume. Therefore the motive iluid contained within thecylinder chamber I6 rotates with the rotor and there will be nodischarge from the cylinder I6 through the port 21. and

I there will be no transfer of the motive fluid to It will be understoodthat the motive iluid contained vin the decreasing volumetric capacitychambers in the driven member is returned to the intake chambers of thedriving member as previously described.

The cylinder may be moved from the neutral or zero position to cause agradual increase in speed ratio for the maximum range of the mechanismand from the maximum baci;l to zero, and the load is at all timesdirectly connected with the applied power.

The device herein described may be operated to drive the driven memberin either direction with an equal range of ratio adjustment.

In order to eiect reversal of operation .of the driven member the bars20 and 2| are rotated so that the valve portion 32 ofthe bar 20 will becaused to extend across the duct 26 to shut oil' the ow of pressurefluid from the driving member to the driven member. concurrently thevalving portion 33 of the bar 2| is moved to close the duct 28. Thechanged positions of the valves are indicated by dotted lines.

, This operation of the bars 20 and 2| closes the duct 28 and opens theduct 35 into the ducil 23 so that the pressure fluid ilows into thedriven cylinder chamber I1 through the port 3| which effects a reversalof operation of the rotor I2.

of the respective cylinder chambers.

y When the machine is in operation centrifugal force holds the vanesoutward but the floating rings engaging the shoulders in the ends of thevanes retain the vanes in constant operating contact with the cylinderwall.

In order that enective contact will be maintained between the outwardedges of the varies and the inner surface of the cylinder chamber eachof the vanes is preferably formed with a part-circular recess extendingfrom end-to-end thereof in which is mounted a semi-circular shoe 39, theouter surface of the shoe making e, uniform contact with the cylinderwall and said shoe having a rotative contact with the vane.

If it is desired to alter the onset of the driving and driven shafts,the bearing bushings, in which the bearings are eccentrically arrangedmay be rotated in the supporting bosses in the outer casing and therelative-rotation will move the respective axes of the driving anddriven shafts into closer or farther separated relation thereby alteringthe relative values between the driving and driven elements.

A transmission device such as described is extremely simple in itsconstruction. It is very rugged and will effectively withstand muchabuse. It affords a very wide range ofspeed transmission from zero tothe maximum capacity for whichv the individual unit is designed;

'I'he connecting ports between the driving and driven members anord afree unthrottled passage of the fluid and-a device of very highefficiency is produced.

A relief valve l0 is shown in Figure 1 threaded into an opening 4Ileading from the passage 26 to the interior of the outer casing 2.

The rotary valve members shown show a highly desirable means forslidably supporting the cylinder and these valves may be operated inunison by means of suitable gear connections or, as illustrated inFigure 9, one valve may Vbe provided with a radial arm having a' pinslidably engaging a slotted radial arm secured to the other valve sothat on the rotation of the upper valve to the dotted position shown inFigure 1 will also rotate the other valve to thedotted position.

What I claim as my invention is:

l. A variable speed hydraulic transmission having a pair of vane typerotors mounted on lparallel but longitudinally onset axes and a cylinderenclosing both of said rotors and engagingthe vanes thereof and mountedfor adjustment in a direction transverse to the axes of said rotorswhereby the volumetric displacement per revolution of the driving rotoris utilized'to drive the other rotor in a direct ratio tothe adjustmentof the enclosing cylinder, in which the cylinder is provided with adividing wall intermediate of its length forming -a pair of cylinderchambers each of said chambers having ports in its periphl eral wall.said cylinder wall having longitudinal passages directly connecting aport of one cylinder chamber with a port of the adjacent cylinderchamber.

2. A variable speed hydraulic transmission as claimed in claim 1, inwhich the dividing wall is formed with transverse passages connectingthe passages between the cylinder ports intermediate of its length, andlvalve means are arranged in said longitudinal passages to direct thenuid now through the transverse passages to reverse the flow of fluid tothe driven rotor.

3. A"Y variable speed hydraulic transmission comprising an outer casing,a pair of parallel cylindrical bars extending transversely of saidcasing and having transverse portions cut-away intermediate of theirlength and forming valves, a cylinder slidably mounted on said barswithin said outer casing and having fluid passages ex-l tendinglongitudinally of the wallsthereof intersecting the cut-away portions ofsaid bars, a wall dividing said cylinder intermediate of its length andforming within said cylinder a pair of cylinder chambers, each of saidchambers having peripheral ports. communicating with the ends of saidlongitudinal nuid passages, said dividing wall having transversepassages communicating with said longitudinal passages intermediate oftheir length and said transverse passages each having one end opening tothe longitudinal passages for sliding said cylinder on said paralleltrans-- verse bars. l y

4. A variable speed hydraulicV transmission as claimed in claim 1 inwhich the dividing wall between the cylinder chambersl is formed with apair of diagonally crossing independent passages the adjacent ends ofboth of which communicate with opposite longitudinal passagesintermediate of their length, a rotary valve arranged in each of saidlongitudinal passages controlling the flow of fluid therethrough todivert same through said diagonal passages.

5. A variable Aspeed hydraulic transmission comprising an outer casinghaving end bosses, bearing bushings mounted in said bosses havingbearings eccentrically arranged therein, the bearings in one bushingbeing onset longitudinally in relation to the bearing in the otherbushing, a drive shaft mounted in one bearing, a driven shaft mounted inthe other and onset bearing, a vane type rotor mounted on each ofsaidshafts, a cylinder having a cylinder chamber enclosing each of saidrotors.- means supporting said cylinder for lateral movement transverseto the axes of said shafts within said outer casing, and means withinsaid cylinder walls for directing the ilow` der mounted for adjustmentwithin said outer casing in a direction transverse to the axes of .saidshafts, rotors mounted on said shafts within said cylinder and havingradial vane slots, vanes slidably mounted in said slotsv and havingrecessed ends, and noating'rings mounted at the- ROBERT s. snaswoa'rn.

